Hi
What You can do is set up an online form that users can submit and it contains their usersname and password then you can get the request to your e-mail and send the validation to them yourself..
Otherwise i think such an add on requires a plug in.. or it might even be included in IAN newsletter plug in that is coming shirtly "I think"
Regards
KaTaBd
Users plug In - Multi Search And Remote Search plug in - WebRing plug in - Muslims Directory